Big Sean, who previously dated Naya Rivera, had announced that they were engaged last October - just six months after going public with their romance. However, the two separated in April.

"Sean is completely smitten with her and adores her," the insider went on. "He's always telling her how happy he is he didn't end up marrying his ex, Naya Rivera, because Ariana is his true love."

Meanwhile, Grande, who previously dated Australian star Jai Brooks and The Wanted's band member Nathan Sykes, had opened up about her bond with Big Sean.

"I love working with him, obviously. We've done many songs together... we even have a few that y'all haven't heard yet, so yeah, I love making music with him. He's very talented," she told Extra's Mario Lopez.